The plastic ones are behind a grey with red stripe F7A that is battery operated and seems to have been available more in England or Europe and made in Hong Kong.

The metal cars we're all familiar with were made by Tenshodo for Marx and are unmarked... the Tenshodo cars are identical but are made of brass with interiors and the bottom of the floors are marked Tenshodo. The Marx cars used the same Bloomberg trucks as those under their engines. More information on that is in the Trucks section. These cars were produced starting about 1958.

The car on the top is the Marx car and the one on the bottom is the Tenshodo car.

The top photo is the Tenshodo observation car. The bottom photo is the Marx car. Note the different trucks ... note the Tenshodo cars have interiors. The Tenshodo cars were available in Santa Fe, New York Central and maybe Pennsylvania. The Marx cars were available in only the Santa Fe.